The House of Olaso is a Basque noble family originally from Trapagaran. Jośe Rufino de Olaso y de la Puente (1839–1918) was granted the rank of Marquess by Pope Pius X on 15 January 1914. His son Luis Saturnino Julián de Olaso y Madaria (1880–1947), the 2nd Marquess, obtained the formal recognition of the title in the Kingdom of Spain on 13 March 1920.[1] The 4th Marquess of Olaso was a shipowner in Bilbao.
Jośe Rufino de Olaso's older brother Julián de Olaso (1832–1910) emigrated to Argentina where he became a wealthy business magnate. He then returned to Spain, where he settled in Bilbao and became the Argentine Consul.[2]
The Olaso Palace in Trapagaran and the Palace of the Marquesses of Olaso (Palacio del Marques de Olaso) in Neguri were built for the family.